Thermal insulating material and method of making the same



July 30, 1935.

K. w. HUFFI'NE THERMAL INSULATING MATERIAL AND METHOD OF MAKING THE SAME Filed April 7, 1932 INVENTOR Kenneth WHzz/fine. 7

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' ATTORNEY Patented July 30, 1935 UNITED f STATES- PATENT OFFICE Kenneth W. Hufiine, Alexandria, Ind., assignor to Johns-Manville Corporation, New York,

N. Y., a corporation of New York Application April 7, 1932, Serial No. 603,763

Claims.

This inventionrelates to a new and improved thermal insulating article and method of making the same as described in the specifications and illustrated in the appended drawing.

One method of insulating a wall, such as an outside wall in a dwelling, is the placing of lightweight material between the studs which support, on one face, the outside wall of the building and, on the other face, the inside wall. Fibrous material is much used in this manner.

If the fibrous material is used without a support, the material may settle, with consequent development of cracks or free space in the wall. For this and other reasons, there is sometimes used a support, such as metal lathing, to which one side of a bat of fibers is attached. The lathing itself may extend over the inside face of the studding and be nailed thereto. Among the ob- J'ections to this structure are the facts that the expanded metal lath does not prevent circulation of air through the bat of fibers and that it is not always desired to have the support extending over the inside face of the studding. As a means of overcoming the objections to this type of support, there have been proposed other means for preventing circulation of air through the bat and for prevention of collapse or settling of the fibrous material. Thus there have been used an outer wrapping or envelope of paper. The fire hazard in having this paper in the wall of a building is evident. Furthermore, the paper gives to the insulation 2. surface which is not as desirable as the soft, yieldable fibrous exterior of the bat itself, as will appear hereinafter.

The present invention is illustrated in the drawing in which Fig. l is a perspective view of a form of insulating material that is the one preferred at this time.

Fig. 2 is a cross sectional view along the line 22 of Fig. 1.

Fig. 3 is a perspective view illustrating the attachment of the insulating structure of Fig. l to externally placed laths, for nailing into position between the studding in a wall, in a modification of the invention.

Fig. 4 is a perspective view of another modification in which the preferred continuous stiffening member is replaced by a rigid frame.

Fig. 5 is a perspective view of another modification in which the continuous stiffening member is not corrugated as in Figs. 1-3, but is of plain surface. Fig. 6 is a perspective view of an incomplete .tion of the outer wall being constructed in accordance with the invention.

Fig. 7 is a perspective view of a modified unit comprising a reenforcing member, felted rock wool fibers spirally wound thereabout, and an 5 enclosing envelope.

In the various figures, like reference characters denote like parts. Thus, I denotes fibrous material, suitably loosely felted, wrapped around a centrally dispose-d stiffening member 2, which is 10 continuous and adapted to serve as a draftbreak, that is, to prevent circulation of air through the bat, from one face to the other, as well as to reenforce the bat. The bat may be attached to exterior wood laths 3, as by staples 4. Such a 5 structure is adapted to be inserted between studding and held in a wall which is not provided with a continuous structure adapted to receive nails. In place of the continuous stiffening member described, there may be used, in special cases described later, a light but rigid frame 5. This frame mayhave strips 6 extending at the corners of the frame beyond the dimensions of the bat and adapted to be bent over to provide spring corners I0 (Fig. 6) for holding theinsulating bat securely between studs in a wall.

The envelope I3 may be asbestos paper, suitably waterproof, and may be sealed, along the flap I4, to exclude moisture. This envelope has some disadvantages, even when used in association with the inner stiffening member; the enveloped bat is not the embodiment of the invention preferred at this time.

The use of a stiifening member I I of plain surface is illustrated in Fig. 5.

The wall structure illustrated in Fig. 6 shows upright studs 1, with plain side faces, and a porwall 8, consisting in this case of board sheathing. Between the studs are inserted the insulating bats or pads. These bats may be held in position by the snug fitting of the bat between the studding and against the sheathing, as illustrated at 9, by a nail I1 inserted through the pad and stiffening member and into the outer wall 8, in which case the nail secures the stiffening member at the selected height in the wall, and the stiffening member, in turn, supports the fibrous felt wrapped around the stiffening member, by a nail or nails I2 driven through the edge of the insulating material and into the sides of the supporting studs, as illustrated, or by the turned-over extensions ID of the stiffening member, or by slats I 5 provided with nails I6 extending through the bats and into the outer wall.

The outer surface of the preferred insulating Mineral wool felt thus unit is fibrous and yieldable, fits snugly into the space available and even into some of the irregularities on the supporting surfaces, and minimizes circulation of air between the insulating material and the supporting surfaces.

It will be evident that the invention provides simple means of producing insulating units sufilciently cheaply for building insulation.

The fibers which are preferred at this time, for the purpose of the present invention, are of the type of those made by melting and blowing an argillaceous limestone and know as rock wool. Other fireproof fibers may be used, as for example, mineral fibers such as asbestos or slag wool. The term rock wool is used herein to include such mineral fibers. Combustible fibers are not recommended, vegetable fibers being usable only in certain cases where fire resistance is not a factor. The term fireproof is used herein to mean noncombustible or ignitable with difficulty, not to mean freedom from injury, by fusion or otherwise, on long exposure to very high temperatures.

In one mode of practicing the invention, the fibers that are to be used are first formed into a loose, aeriformed felt, in a manner similar to that described in Powell, U. S. Patent 1,656,828, issued January 17, 1928. Thus, a loose felt of rock wool may be formed by collecting the fibers,as blown, in a settling chamber provided with a moving conveyor at the bottom. The felt may be allowed to form, on the conveyor, to thicknessesdesired, as, for example, to 1 inch, and subjected to a very slight compacting action of a roll or the like. formed may be conveyed over a table and there spirally wrapped by hand around fiat corrugated cardboard in pieces that are approximately as long as the felt is wide and of width selected to give a finished insulating article of width desired. The cardboard is suitably faced on one side with plain paper adhered thereto, as illustrated at 2, in Fig.2. After the felt has been wrapped around the cardboard, to form a pad or hat of the desired thickness, as,- for example, 1 to 3 thicknesses of the felt to each side of the cardboard-stiffening member, the thus formed bat is severed, as by cutting it from the rest of the sheet of felt. The bat is then cut into lengths desired, suitably by a saw. This gives a product such as illustrated, for example, in Fig. 1, that is self sustaining.

Supporting the felt thenon the wrapping table, that is, continuously from the time of its formation until it is formed into a self sustaining unit, makes possible the winding of a very weak and light felt of frangible fibers into bats of the kind described.

effectual in house insulation, '10.

Units may thus be made size desired, within limits. Thus they may be made ofsuch dimensions as to fit between studding of standard spacing, as, for example, approximately 18 inches long by inches wide and 3 inches thick. Several such bats may be laid in a shipping carton, with a plain sheet of thin paper placed between the various bats in order to prevent their outer surfaces from becoming more or less interlocked during shipment and handling.

It will be understood that aeriformed mineral wool, particularlyrock wool, felt is exceptionally but is particularly weak as compared to more usual types .Of felts.

The reenforcing of the mineral wool felt with the inwardly placed stiffening member preserves the. outstanding utility of the felt in house insulation and, at the same time, overcomes the objection of weakness. The resulting bats may be roughly on the conveyor belt and to have almost any rectangular, with two rounded edges formed by the spiral winding of the felt around'the stiffening member. The continuous sheetv of felt, disposed around the stiifening member, minimizes the tendency of the latter to bend or buckle after 'as for example, by means of perforations in the interior face of the wall enclosing the bat. Also, the stiffening member of preferred form, being continuous, that is notforaminous or perforated, is effective in decreasing the circulation of air through the bat. At the same time, the stiffening member, such as cardboard, may be flexed when the bat is inserted into the wall space. Being springy or resilient, the cardboard will tend to straighten out, and thus increase the thoroughness of contact of the yeldable exterior of the insulating bat, with the supporting surfaces in the wall. When made with rock wool and having a total thickness of 3 inches, the product described may weigh approximately 12 pounds or less per cubic foot. The specific thermal conductance is less than 0.40 British thermal units and usually approximately 0.27 British thermal units, calculated to 1 inch of thickness. (It will be understoodth'at the specific thermal conductance is the quantity of heat transferred per square foot per hour for each degreeF. of temperature difference between the two sides of the insulating article, when the thickness of the insulating article is 1 inch.) For a pad 3 inches thick, the heat transfer would be approximately 0.09 British thermal units, that is, a third as much as through a 1 inch layer of material of the same average composition. The simple calculations are made inaccurate to a slight extent by the presence of a stiffening member within the bat.

Although the stiffening member, used may be combustible, as in the case of cardboard, the finished article is fire resistant to a high degree. The thick, insulating, fibrous covering of the cardboard protects the cardboard from ready ignition by an external source of heat, such as a burning match. Usually the fibrous material, during shipment and handling, comes to extend somewhat over the end of the stiffening member, at the position where the process of manufacture. This effect is probably caused by the slight compression of the loose felt, with consequent increase in its length. In any case, the ends of the cardboard may be further protected in the finished wall assembly by abutment with the edges of the adjacentpads or against the sides of studding or other support members.

The structure illustrated in Fig. 4, in which a frame is substituted for the continuous stiffening member of the preferred embodiment, is satisfactory for installation in walls in which cross circulation of air is not a factor. The material the article was cut during standpoint ably first cut to width required to suit the width of the frame. A convenient length of the ex tensions 6 is 1 to 1 inches beyond the edge of the bat. The extensions may, of course, be omitted from the frame, if their wedging action in the finished wall structure is not desired.

In the use of the product of the invention as building insulation, 2. wall is partly assembled, as, for example, to the extent that the upright studding are erected and also a part of the outer wall. In case the wall has sheathing, such as 8, the bats are then pushed into position between the studs and, if they are to be secured by nails, are nailed either to the side of the studding or to the sheathing. In case the sheathing is not continuous and it is desired to secure the bats to discontinuous horizontal nailing strips or other members, the laths illustrated in Fig. 3 may be attached to the reenforced insulating bats and then nailed to the horizontal members. It will be obvious to one accustomed to such constructions that the bats may be made to abut with each other, by extending the laths attached to one bat behind an adjacent bat and also that this abutment will be facilitated by spacing the laths on adjacent hats at different distances apart so that the laths on one bat will not interfere with, that is, will not strike those on the adjacent bat.

After the bats have been placed in the wall, then the interior of the wall may be finished in conventional manner, as by applying lath over the inside face of the studding and then plastering. The final result is a structure comprising outer and inner walls defining a space between them that is filled with the improved insulating material. The wall is very effective, from the of thermal insulation, minimized circulation of air from the outside to the inside face of the wall, and, so far as the insulation is concerned, fire resistance. Further, the structure is vermin and ferment proof, in further distinction from the result of insulating with fibrous material containing, as stiffening agent, certain conventional organic binders.

Corrugated cardboard faced with adhered plain paper, enclosing air spaces, is light in proportion to its stiffness, and has also an insulating effect of its own that is not shared by heavy stiffening materials, such as iron or the like. Other stiffening members that are suitably light-weight, semirigid, and continuous in form, may be used. Because of their low density, organic materials, and particularly cellulosic substances, are preferred in the stiffening member. Strawboard of corrugated or plain surface may be used.

In some cases, the stiffening member may be replaced by a central portion of the bat comprising the same type of fibers as the rest of the hat, but made semirigid by the application of a suitable binder thereto. Thus a slab comprising rock wool and an asphalt binder may be wrapped with loosely felted rock wool, to give a reenforced bat. However, such a structure is unnecessarily expensive, usually moreheavy and rigid than required or desired for the purpose of building insulation, and not adapted to be sprung as satisfactorily into place as the preferred form of bat.

In some cases,'it is desirable to have a waterresistant envelope for the exterior of the bat that will not affect to a substantial degree the fibrous and yieldable character of the exterior. Such a coating should be also fire-resistant, for most purposes.

In making. a bat with such a coating, the folowing procedure may be used. A bat of the type illustrated in Fig. 1, for example, is made as described, and then sprayed with a composition containing the desired waterand/or fire-resistant material. Thus, the bat may be sprayed with a water solution of sodium silicate, and then dried.

' There is thus formed an outer semiflexible coating of waterand/or fire-resistant material that is integrally united to the bat.

The temperature at which the sprayed bat is dried should be below that at which weakening of the felt or stiffening member occurs. In case the stiifening member is vegetable cardboard, for example, the temperature of the bat, during drying, should not greatly exceed 212 F. for any long period.

Or, the bat may be made water-resistant by means of a conventional waterproofing agent, as, for example, by a bituminous coating or by aluminum stearate applied in convenient manner. Thus the bat may be sprayed with a dilute solution of aluminum stearate in a mixture of gasoline and benzol, and then submitted to an elevated temperature to expel the gasoline and benzol.

Such integrally united outer coatings should usually be so thin as to leave the outer surface of the bat yieldable and flexible. However, in special cases, where this character of outer surface is not desired, the waterand/or fire-resistant material may be applied to form a thick and more or less rigid coating.

In the structure of the present invention, the stiffening member can be made to maintain roughly the desired length and breadth of the insulating article. By maintaining the length and breadth of a bat containing a definite numher of wrappings of felt of definite thickness, the thickness also of the bat is maintained roughly, in distinction from the case in which a bat, not being maintained as to length and breadth, might collapse on itself, with consequent effect upon its thickness.

Since many variations from the illustrative details'that have been given maybe made without departing from the scope of the invention, it is intended that the invention should be limited only by the terms of the claims.

What I claim is:

1. Lightweight building insulation of outer surface that is fibrous and yieldable and adapted to be inserted between studding in a building wall, said insulation comprising in combination a continuous stiffening member of little weight in proportion to its stifiness and fireproof aeriformed felt disposed around said stiffening member.

2. Lightweight building insulation of outer surface that is fibrous and yieldable and adapted to be inserted between studding in a building wall, said insulation comprising in combination an organic stiffening member of low density in proportion to its stiffness and fireproof fibrous material wrapped around said stiffening member, whereby the stiffening member is protected from ready ignition ,by an external source of heat.

3. An insulating unit comprising in combination centrally disposed stifi' sheet material encased in a spirally wound layer of loosely felted mineral wool.

4. A lightweight, thermal insulating article, of predetermined approximate length and breadth, weighing approximately 12 pounds per cubic foot, and comprising in combination a corrugated cardboard stiffening member and loosely felted rock wool fibers wrapped around said stiffening mem- -heat and the stiffening member maintains roughly the type of cardboard and felted fire-resistant fibers disposed around said stiffening member, whereby the fibers protect thestifiening member from ignition by an external source of heat and the stiffening member maintains roughly the desired length and breadth of the article..

6. A lightweight, thermal insulating article, oi. predetermined approximate length and breadth, comprising in combination a corrugated cardboard stifi'ening member and loosely felted mineral fibers wrapped around the said stiffening member, whereby the fibers protect the stiffening member from ignition by an external source of heat and the stiffening member maintains roughly the desired length and breadth of the article and serves as a draftbreak.

7. A lightweight, thermal insulating article, of outer surface that is fibrous and of predetermined approximate length and breadth, having a specific thermal conductance of approximately 0.27 British thermal units, and comprising in combination a fiat semirigid stiffening member and loosely felted rock wool fibers wrapped around said stiffening member, whereby the fibers protect the stiffening member from ignition by an external source of heat and the stiffening member maintains roughly the desired length and breadth of the article.

8. A lightweight, thermal insulating article, of predetermined approximate length and breadth, comprising in combination a semin'gid cellulosic stiifening member and loosely felted rock wool fibers wrapped around said stiffening member, whereby the fibers protect the stiffening member from ignition by an external source of heat and the stiffening member maintains roughly the desired length and breadth of the article.

9. A lightweight, fire-resistant, water-resistant, thermal insulating article comprising in combination an inwardly disposed stiffening member, a fireproof felt disposed around said stiffening member to produce a reenforced fibrous bat, and an outer semiflexible sealing envelope of water and fire-resistant material integrally united to the bat.

10. A lightweight, water-resistant, thermal insulating article comprising in combination an inwardly disposed stiffening member, a fireproof felt disposed around said stiffening member toproduce a reenforced fibrous bat, and an outer semiflexible sealing envelope of water-resistant material integrally united to the bat.

11. A lightweight, fire-resistant, water-resist- 13. In making a lightweight thermal insulating article including an inwardly disposed stiifening member, a loose felt of fibrous material wrapped around said stifl'ening member, and an outer, integrally united coating of water-resistant material, the step which comprises wrapping the felt around the stiffening member to form a reenforced bat and applying a composition containing the water-resistant material over the outer surface of the bat.

14. In making a lightweight thermal insulating article including a loose felt of fibrous material and an outer, integrally united coating of waterresistant material, the step which comprises wrapping the felt around the stiffening member to form a reenforced bat and applying a solution of the water-resistant material over the outer surface of the bat, and then drying the product at a temperature below that at which weakening of the felt or stiffening member occurs.

15. In making a thermal insulating bat including an inwardly disposed shape-establishing reenforcing member and fibers disposed therearound, the method which comprises supporting substantially continuously an aeriformed loose felt of frangible fibers of the type of mineral wool and wrapping the felt, while in the condition of being supported, around the said reenforclng member until the said member is covered by a layer of fibers of the desired thickness.

KENNETHWHUFFINE. 

